The asbestos issue is an extremely complex one which cannot be easily addressed with broad, sweeping conclusions or regulatory policies. Researchers, industrial hygienists and government regulators are having to evaluate which types of asbestos fibres, with which characteristics, under what exposure conditions, for what periods of time result in increased risk. To further complicate the issue, they must also take into consideration the health risks of materials which are proposed as replacements. Regulatory agencies have the added burden of having to consider the cost-benefit implications of the emerging scientific data and how it should impact on policy decisions. These and other issues are examined in greater detail in Module 9 which reviews the international regulatory environments for chrysotile.